Failed To Convert parameter value from a String to Guide

I tried to pass a GUID parameter to a method that calls on a stored procedure but I'm getting errors. How do I pass uniqueidentifiers to stored procedures in my C# code? And my stored procedure needs GUID parameter

This is my c# code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;